My team has had success with using Gather.Town as well! The only downside is that it is a little unwieldy, in that you have to be careful where you are positioned so that you don't accidentally lose contact. The "rules" of what constitutes a shared space and when you have to rely on proximity, are also a little unclear.
They're configurable. In our Xmas party house the entire kitchen is one broadcast domain, like the kitchen at a party. But in the local pub we built for Friday evenings we have "booths" and you must sit down in the booth to talk to people in that booth. By default it's just proximity, so like a real pub there were always two or three girls in the toilets having presumably a private chat.
So you do need somebody technical to make the space work how you need, and if your users are all non-technical you probably only want one type of rule everywhere or it'll confuse them.
It's down to the design of the space. We made our own, and "Private Spaces" were visually distinguished by "carpets" ... it made a huge difference. The rules for shared space vs proximity are very clear, but the design of the graphics need to be clear and consistent.
